Circularization and Tidal Dissipation in Eclipsing Binary Stars

This work studies orbital circularization of binary
stars past the Main Sequence using two new samples of
eclipsing binary stars found in the Magellanic Clouds
by the MACHO Project, as well as samples introduced
by the OGLE-II project and finds strong evidence of
orbit circularization past the Main Sequence phase of
stellar evolution, by the almost complete absence of
systems with eccentric orbits in the Red Giant part
of the Color Magnitude Diagram whereas the Main
Sequence exhibits systems with a broad range of
eccentricities.
This absence allows to robustly conclude that binary
stars
circularize their orbits either on crossing the
Hertzsprung Gap or on ascending the Red Giant Branch
when they undergo a sudden and dramatic increase in
their dimensions resulting in strong tidal forces
that disrupt the orbit.
The work then quantifies the effects of tidal
interaction and distortions via a a thorough study of
the Specific Dissipation Function Q, which is
generally not well known for binary stars and finds
evidence of a low degree of tidal dissipation.

Autorentext
Lorenzo Faccioli is currently a postdoctoral researcher at the University of California at Berkeley working on Supernova Cosmology. He has degrees in Physics and Electrical Engineering from the University of Bologna, Italy, and a PhD in Physics and Astronomy from the University of Pennsylvania working on eclipsing binary stars.

Klappentext
This work studies orbital circularization of binary stars past the Main Sequence using two new samples of eclipsing binary stars found in the Magellanic Clouds by the MACHO Project, as well as samples introduced by the OGLE-II project and finds strong evidence of orbit circularization past the Main Sequence phase of stellar evolution, by the almost complete absence of systems with eccentric orbits in the Red Giant part of the Color Magnitude Diagram whereas the Main Sequence exhibits systems with a broad range of eccentricities. This absence allows to robustly conclude that binary stars circularize their orbits either on crossing the Hertzsprung Gap or on ascending the Red Giant Branch when they undergo a sudden and dramatic increase in their dimensions resulting in strong tidal forces that disrupt the orbit. The work then quantifies the effects of tidal interaction and distortions via a a thorough study of the Specific Dissipation Function Q, which is generally not well known for binary stars and finds evidence of a low degree of tidal dissipation.